1. Field of the Invention
The present invention relates to a mobile communication system, a mobile terminal, a subscriber information management apparatus, a mobile network system, a location area information registration method and a call control method, and more particularly to a mobile communication system, a mobile terminal, a subscriber information management apparatus and a location area information registration method in which outgoing calls and incoming calls using a plurality of telephone numbers, mail addresses, etc. can be performed by loading a mobile terminal with a plurality of recording media (e.g. SIM cards), and a mobile network system and a call control method performing call control related to such mobile terminal.
2. Description of the Related Art
A system that separately includes a mobile terminal and an IC card that serves as a recording medium such as an SIM (Subscriber Identity Module) card for storing subscriber information, is implemented in the GSM (Global System for Mobile Communication). Currently, the GSM offers card type and plug-in type SIM cards.
FIG. 1 is a schematic diagram showing a conventional mobile communication system employing mobile terminals using SIM cards.
The mobile communication system comprises at least a mobile terminal 10, a base station (BSS) 20 and a mobile network (system) 30. The mobile terminal 10, which carries out radio communication with the base station 20, has a detachable SIM card 12 storing its own IMSI (International Mobile Subscriber Identity). The base station 20, which is connected to the mobile network 30, carries out radio communication with the visiting mobile terminal 10. The mobile network 30, which comprises at least a mobile switching center (MSC) 40, a visitor location register (VLR) 50 and a home location register (HLR) 60, carries out line switching or packet switching of the mobile communication. The mobile network 30 can utilize an existing PDC (Personal Digital Cellular) mobile line switching network or PDC-P (Personal Digital Cellular-Packet) mobile packet switching network. As for the PDC and PDC-P, however, the home location register achieves the function of the visitor location register. The mobile switching center 40 is a switching center in the mobile communication network. The visitor location register 50 is a database of the subscriber information needed for controlling the mobile terminal 10 in the visited area controllable by one or more mobile switching offices. The home location register 60 is a database storing the original subscriber information on the service contract of each mobile terminal 10.
Here, assume that a person B has two SIM cards 12, an SIM card 12-1 of A corporate contract and an SIM card 12-2 of B personal contract, and uses the mobile terminal 10-1 mounted with the SIM card 12-1, and the mobile terminal 10-2 with the SIM card 12-2, and that the mobile terminal 10-1 is in an area with a location area ID1 (LAIL: Location Area Identification 1) that is set by the mobile network in the A corporation, and the mobile terminal 10-2 is in another area with a location area ID2 that is set by the mobile network.
FIG. 2 is a diagram showing information stored in the databases of the conventional HLR and VLR. The HLR database stores at least telephone numbers, subscriber identity information (IMSIs: International Mobile Subscriber Identities) and VLRs of the visited areas by the mobile terminals. On the other hand, the VLR database stores at least telephone numbers, subscriber identity information (IMSIs) in the visited area managed by the VLR, temporary subscriber identity information (TMSIs: Temporary Mobile Subscriber Identities), location area IDs (LAIs) and communication state.
For example, the example shown in FIG. 1 has the databases storing the information as shown in FIG. 2.
Then, the mobile network 30 temporarily stores call records (start time and end time of the calls) of individual telephone numbers, so that the mobile network 30 transmits the telephone numbers and call records to a charge system that computes charges of the individual telephone numbers.
However, the conventional mobile terminal 10 cannot mount a plurality of SIM cards 12 thereon. Thus, to use the corporate contract SIM card 12-1 and the personal contract SIM card 12-2, it has a problem of making it necessary to replace the SIM cards 12, or to use a plurality of mobile terminals 10 such as the corporation mobile terminal 10-1 and the personal mobile terminal 10-2.
In addition, there is another problem involved in separately billing the users sharing a single telephone number. Although the PDC system enables individual users sharing its single telephone number to receive their own bills by adding, when making a call, a predetermined number assigned to each user for separate billing before the called number, it presents the following problems. First, it is necessary for the users to add the special numbers every time they make a call. Second, this service does not send the bills to the respective users of the telephone contracted. As a result, there is another problem in that it is necessary for the contractor to adjust the charges of the individual users.